Indole Synthesis via Rhodium Catalyzed Oxidative Coupling of Acetanilides and Internal Alkynes

Beyond Traditional Cross Couplings: The Scope of the Cross Dehydrogenative Coupling Reaction

“…[52] Fagnou and co-workers have reported the Rh-catalyzed intermolecular cyclization between alkynes and N-acetyl anilines. [53] Both of these methods represent significant advances for C À H activation, however, both of these methods suffer from the fact that they require directing groups for the coupling to proceed. Recently, Jiao and co-workers have reported the use of a palladium catalyst of the synthesis of indoles from anilines and alkynes using molecular oxygen as the oxidant, Scheme 33.…”

Construction of indole nucleus through C-H functionalization reactions

“…Fagnou and co-workers 62 reported an interesting rhodium-catalyzed intermolecular cyclization between alkynes and N-acetyl anilines (Scheme 46). The key step is an acetamide directed C-H insertion reaction to give reactive intermediate 15.…”

Eco-Friendly, Catalyst and Solvent-Free, Synthesis of Acetanilides and N-Benzothiazole-2-yl-acetamides

“…Besides, the reactivity of some ortho functional group of acetanilides is modulated by the presence of the N-acetyl moiety, which is thus selectively converted to more complex compound, constituting this kind of acetanilide into important synthetic intermediates. 5,[9][10][11][12][13] Due to the abovementioned applications, new developments in the acetylation procedure are still desirables, and representative contributions are described, Figure 2. [14][15][16][17][18][19][20][21][22][23][24] Furthermore, in undergraduate courses, the parent acetanilide is extensively synthesized as classical preparation of aromatic amide.…”

“…Besides, the reactivity of some ortho functional group of acetanilides is modulated by the presence of the N-acetyl moiety, which is thus selectively converted to more complex compound, constituting this kind of acetanilide into important synthetic intermediates. 5,[9][10][11][12][13] Due to the abovementioned applications, new developments in the acetylation procedure are still desirables, and representative contributions are described, Figure 2.14-24 Furthermore, in undergraduate courses, the parent acetanilide is extensively synthesized as classical preparation of aromatic amide.25 Therefore, we recently developed a practical solvent-free green synthesis of such compound to experimental courses. 26 However, a search in the literature revealed that when other substituted acetanilides are needed as starting material in the context of a research project, the preparation used is very similar to that of parent acentanilide, which is almost the same of one century ago, which uses large amounts of solvents and additives such as acetic acid and sodium acetate, for instance.…”

“…26 However, a search in the literature revealed that when other substituted acetanilides are needed as starting material in the context of a research project, the preparation used is very similar to that of parent acentanilide, which is almost the same of one century ago, which uses large amounts of solvents and additives such as acetic acid and sodium acetate, for instance. [5][6][7][8][9][10][11][12][13][14][15][19][20][21][22][23][24] It should be pointed out that, although there are a few syntheses of acetanilides in the absence of solvent, it is always necessary the use of grinding or microwave heating in these previously described syntheses or, more recurrent, the use of catalyst such as morpholinium bisulfate, zirconyl triflate, tris(pentaflurophenyl)borate, anatase phase TiO 2 nanoparticles, or even the unconventional rice husk ash, Figure 2. 24 Despite that solvent-free catalyst's dependent approaches represent important contribution, more environmentally friendly procedures which reduce the use of chemicals and energy is still needed.…”